Detection, quantification, isolation, and purification of target biomaterials, such as viruses and biomacromolecules (including constituents or products of living cells, for example, proteins, carbohydrates, lipids, and nucleic acids) have long been objectives of investigators. Detection and quantification are important diagnostically, for example, as indicators of various physiological conditions such as diseases. Isolation and purification of biomacromolecules are important for therapeutic uses and in biomedical research.
Polymeric materials have been widely used for the separation and purification of various target biomaterials. Such separation and purification methods can be based on any of a number of binding factors or mechanisms including the presence of an ionic group, the size of the target biomaterial, a hydrophobic interaction, an affinity interaction, the formation of a covalent bond, and so forth.
Membrane-based technologies, especially in disposable format, are becoming increasingly important in biopharmaceutical and vaccine manufacturing processes. Membranes have been used in passive, size-based separations (for example, in virus removal applications) and, more recently, in active filtration (for example, for the removal of minor contaminants in later stages of purification processes).
Functionalized membranes (including functional polymer-bearing membranes) have typically suffered from relatively low biomaterial binding capacities, however, and this has generally limited their use in large-scale purifications. Porous beaded chromatography resins (bearing ion exchange or other interactive ligand functional groups), rather than functionalized membranes, therefore have been standardly used in “capture-and-elute” type protein purification processes.